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<meta charset="utf-8">
<body>
<script src="https://d3js.org/d3.v5.js"></script>
<script src="https://unpkg.com/viz.js@1.8.1/viz.js" type="application/javascript"></script>
<script src="https://unpkg.com/d3-graphviz@2.1.0/build/d3-graphviz.js"></script>
<div id="graph" style="text-align: center;"></div>
<script>

  d3.select("#graph").graphviz(false)
      .renderDot('digraph  {a -> b}');

</script>
